황요하 2024-01-13T00:03:32Z 2024-01-13T00:03:32Z 2003-01-09 https://pubs.kist.re.kr/handle/201004/100005 내연　기관의　배기　소음　능동　제어장치　및　방법 Patent 2003-01-09 2000-04-19 0369212 2000-0020535 KO 특허 한국과학기술연구원